De-coupling device for sheet reversing mechanism

ABSTRACT

The present invention aims at providing fully automated de-coupling device with smooth switching operation and durability. Basing upon mounting ring  16,  regulating gear  20  is disposed in parallel with fixed gear  18  to shaft  10  of reversing cylinder. Pressure lever  32  tightens the regulating gear  20  to the reversing cylinder by lever principle. One end of the pressure lever  32  is urged by plate spring  28  at the center of the shaft  10  and, by temporally breaking off thrust of plate spring  28,  the regulating gear  20  is released. Shifting member  34  for temporally breaking off thrust against the plate spring  28  has a pair of screw bolt  36  and nut  44  and is co-axially positioned with the shaft  10.  One end of screw bolt  36  is regularly engaged with power source  48  and the other end can be pressed onto the pressure lever  32  in opposition to plate spring  28.  The screw nut  44  is pivotally attached via radial bearing  54  to flange member  22  which is fixed to the end of the shaft  10.  Stay  58  protruded from press body prohibits movement of the screw nut  44  in relation to the press body. Flange portion  52  of screw nut  44  abuts against the flange member  22  via thrust bearing  56.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to sheet reversing mechanism of sheet-fed printing press, or more precisely, to de-coupling device of the reversing construction.

2. Description of the Prior Art

In sheet-fed printing press technique, there are one side printing in which only one surface of sheet is printed and two sides or perfecting printing in which both the front and back surfaces of sheet are printed. In order to switch printing mode, reversing cylinder with mechanism for sheet reversing is disposed between printing units. The reversing cylinder which plays the leading role in sheet reversing movement must be regulated in its phase in accordance with printing mode and sheet length. In concrete, cylinder drive gears of up- and down streams of the reversing cylinder must be mutually regulated in their rotational phases.

Therefore, a fixed gear and a regulating gear are provided in parallel to the end of shaft of reversing cylinder. Each gear is meshed with cylinder drive gears of up- and down streams. Unification of regulating gear must be temporally released for phase adjustment and then the regulating gear is coupled again.

Japanese patent laid-open No. 237161/1987 discloses de-coupling structure in which pressure disc urged by plate spring couples regulating gear with fixed gear of reversing cylinder and such coupling is released by pressure lever based upon lever principle.

But, the device can only be manually operated, not automated.

By Japanese patent No. 2924991, regulating gear is coupled by movable pressure rod which is co-axial with cylinder shaft, plate spring supported by the pressure rod and pressure lever urged by the plate spring.

For de-coupling, an adjusting cylinder actuated by pressure medium is disposed on one end of pressure rod and the rod is moved in the direction of cylinder shaft.

But, such pressure medium method has problems in sealing and difficulty in manufacturing, therefore, results in high cost.

SUMMARY OF THE INVENTION

In view of above-described problems of prior art technique, the present invention aims at fully automated de-coupling device with simple construction, smooth switching operation and durability.

To achieve these objects, de-coupling device according to the present invention comprises a shifting member by a pair of screw bolt and nut in co-axial relation with cylinder shaft. One end of the screw bolt is regularly engaged with power source and the other end can be pressed onto pressure lever in opposition to a plate spring. The screw nut is pivotally attached via radial bearing to flange member which is fixed to the end of the cylinder shaft and flange portion of nut abuts against the flange member via thrust bearing.

According to the present invention, de-coupling force can mechanically be transmitted in regularly engaging state, therefore, clutch means is not necessary and the device can be simplified, resulting in low cost and eliminating troubles. Inner opposition force due to de-coupling operation can be cancelled and excess force on bearing of shaft is prevented. Moreover, adjustment operation is smooth and mechanical durability is improved.

The above and other objects of the invention will become apparent from the following description of preferred embodiment taken in conjunction with the accompanying drawings. However, the following description is only an embodiment of the invention and the present invention is not limited to the embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of de-coupling device according to the present invention.

FIG. 2 is a side view from arrow II in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT

An embodiment of de-coupling device according to the present invention is detailed here-in-under with reference to the drawings.

FIG. 1 is a sectional view of de-coupling device and cylinder shaft 10 represents reversing cylinder (not shown) of printing press and the shaft 10 is rotary supported by a pair of side walls 14 via bearing 12. Mounting ring 16 is fixed to the cylinder shaft 12. A fixed gear 18 in mesh with downstream drive gears is attached to the mounting ring 18 and, in parallel with the fixed gear 18, a regulating gear 20 in mesh with upstream drive gears is adjustably attached to the mounting ring 16. Further, ring-like flange member 20 is fixed to the outside of the mounting ring 16 to cover central room 24 by them. In compliance with the center of shaft 10, pin 26 is set in the central room 24 so as to receive many plate springs 28.

Flange member 22 has radial groove-like rooms 30 between the mounting ring 16 and a plurality of pressure levers 30 by lever principle are disposed in the room 30. As shown, one end of the pressure lever 32 near to the shaft center abuts against the plate springs 28 and screw bolt 36 of shifting member 34 comes in contact with the end. Other end of the lever 32 extending in radial direction has a projection 38 for lever action as well as contact portion 40 for uniting the regulating gear 20 with the mounting ring 16 and reversing cylinder.

Screw bolt 36 can be moved in compliance with the center of cylinder shaft 10 and rotation-free disc portion 42 at its tip end comes in contact with the pressure lever 32. Center portion of the screw bolt 36 engages with screw nut 44 as a pair of shift member 34. Pinion gear 46 is attached to the outer end of the screw bolt 36 and, as shown in FIG. 2 (side view from arrow II in FIG. 1), rack 50 which is moved by power source 48 (such as by air cylinder) regularly engages with the pinion 46. Screw nut 44 which composes shift member 34 with the screw bolt 36 has flange portions 52 at both ends (one of the flange portions 52 is coupled later for assembly convenience). The screw nut 44 is freely supported by radial bearing 54 in relation to the flange member 22. Thrust bearing 56 is disposed so as to receive axial thrust. Stay 58 protruded from the side wall (namely, printing press which stands absolutely still) has rotation stopper 60 (such as by parallel surface blocks) to prohibit rotation of the nut 44. Support stay 62 which further extends from the stay 58 rotary and slidably supports the screw bolt 36. But, such construction is only a matter of design.

Next, de-coupling process by above-described construction is detailed. Power source 48 by air cylinder is actuated after stopping printing press as well as reversing cylinder. Then, the rack 50 is slid to rotate pinion gear 46 and screw bolt 36. The screw bolt 36 which engages with the screw nut 44 moves forward in the axial direction. Then, rotation-free disc portion 42 comes in contact with one end of pressure lever 32 so as to compress plate springs 28 in the opposite direction. On account of compressing plate springs 28, pressing by pressure lever 32 to regulating gear 20 is cancelled and, in this state, reversing cylinder (namely, the fixed gear 18 which is united with the reversing cylinder) is rotated up to the necessitated phase in order to alter relative rotational phase between the regulating gear 20.

After altering mutual rotational phase, screw bolt 36 is reversed by power source 48. Then, the screw bolt 36 moves backward and disc portion 42 parts from pressure lever 32. Thereby, urging by plate spring 28 onto the pressure lever 32 is restored and the regulating gear 20 is coupled again with the fixed gear 18 by the pressure lever 32.

Naturally, inner opposition force arises when compressing the plate springs 28 by screw bolt 36. But, such opposition force is consequently cancelled in the course of screw bolt 36, screw nut 44, thrust bearing 56 and finally, flange member 22 which is united with cylinder shaft 10. Screw nut 44 stands regularly still despite the rotation of reversing cylinder, as radial bearing 54 is interposed between the flange member 22. Moreover, screw bolt 36 is constantly in mesh with up to the power source 48.

The present invention is not limited to the embodiment described above; it can be extended and modified variously.

DESCRIPTION OF THE REFERENCE NUMERALS

-   10 shaft of reversing cylinder -   14 side wall -   16 mounting ring -   18 fixed gear -   20 regulating gear -   22 flange member -   28 plate spring -   32 pressure lever -   34 shifting member -   36 screw bolt -   44 screw nut -   46 pinion gear -   48 power source -   50 rack -   52 flange portion -   54 radial bearing -   56 thrust bearing -   58 stay -   60 rotation stopper 

1. In a de-coupling device for sheet reversing mechanism in which regulating gear 20 is mounted on shaft 10 of reversing cylinder in parallel with fixed gear 18, one end of pressure lever 32 which extends in radial direction being urged by plate spring 28 at the center of the shaft 10, the regulating gear 20 being released temporally by breaking off thrust of the plate spring 28, wherein an improvement comprising; shifting member 34 composed by a pair of screw bolt 36 and nut 44 which are co-axially disposed in relation to the shaft 10, one end of the screw bolt 36 being regularly engaged with power source 48, other end being able to be pressed to tip end of pressure lever 32 in opposition to plate spring 28, the screw nut 44 being pivotally attached via radial bearing 54 to flange member 22 which is fixed to the end of the shaft 10, and flange portion 52 of the screw nut 44 abuts against the flange member 22 via thrust bearing
 56. 